Behind the controls of the Metro-North train that derailed in New York earlier this week was a tired driver, according to new reports that engineer William Rockefeller fell asleep at the wheel.
Could lack of sleep cause such a fatal mistake?
Biologically speaking, experts said, yes. Sleep deprivation affects the brain in multiple ways that can impair judgment, slow reaction times and increase the likelihood of drifting off during monotonous tasks.
"When you're sleep deprived, your brain reverts to a teenager -- it's all gas and no brake," said Michael Howell, a neurologist at the University of Minnesota, Twin Cities. "Suddenly the part of the brain that says, 'Let's think through this,' is not functioning well."
The purpose of sleep has long mystified scientists, said Maiken Nedergaard, a neuroscientist at the University of Rochester Medical Center in New York. In an evolutionary conundrum, lying unconscious for hours on end makes people and other animals vulnerable to predators. Yet, not sleeping for long enough can actually lead to dementia and death. Chronic sleep-deprivation can cause obesity, diabetes, heart disease and other ills.